Communication systems often use transmission signals focused around a carrier frequency of a defined channel. Information is conveyed by representing the information with a modulation based on amplitude, phase, frequency and/or combinations thereof. The information is sent by one or more signals over a band of frequencies around the carrier frequency.
A radio frequency (RF) power amplifier is often used for modulations, such as amplitude modulation. The RF power amplifier is required to operate over wide ranges of frequencies and power levels.
Some important characteristics for power amplifiers include power efficiency and gain. The power efficiency is important in order to reduce power consumption. The higher the power efficiency, the less power consumed. Gain represents the amount of amplification of an input signal to an output signal. A higher gain generates a higher amplitude version of the input signal as the output signal of the power amplifier.